The document provides information about UML (Unified Modeling Language), including its goals, why it is used, and common diagram types. UML is a standard language for specifying, visualizing, and documenting software systems and other non-software systems. It uses mostly graphical notations to express the design of software projects. Common UML diagram types include use case diagrams, class diagrams, interaction diagrams, state diagrams, activity diagrams, component diagrams, and deployment diagrams. Each diagram type displays different aspects of a system and can be used at various stages of development.